A conveyor belt typically includes one or more scraper assemblies that are constructed and disposed along the belt for removing remnants of materials carried by the conveyor belt that adhere to the belt surface. A scraper assembly often includes one or more scraper blades arranged across the width of the conveyor belt. The blades are mounted on a support arm or arms that are affixed to and extend from a transversely mounted, rotatable support shaft. Rotation of the transverse support shaft moves the scraper blade or blades into and out of contact with the belt surface.
The cleaning efficiency of the scraper assembly depends on the magnitude of the force exerted by the scraper blade against the belt surface. If the contacting force is too great, the scraper blade will wear prematurely. On the other hand, if the contacting force is too low, the blade will not clean the belt efficiently. Torsional coil springs, torsion rod springs, air cylinders, hydraulic cylinders, and similar devices are used to adjust the force with which a scraper blade contacts a conveyor belt surface. In pneumatic and hydraulic systems a pressure gage provides an indication that can be correlated with the amount of force being applied. It would be highly desirable to have a tensioning device for a belt scraper assembly that provides an instantaneous indication that can be easily used to reproducibly set the amount of force with which the scraper blade contacts the belt surface.